Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
638 PM EDT Sun May 08 2022
Valid 12Z Thu May 12 2022 - 12Z Mon May 16 2022
...Overview and Guidance/Predictability Assessment...
The 12 UTC GFS/ECMWF/UKMET/Canadian model solutions and GEFS/ECMWF
ensemble means seem reasonably well clustered into Day 4/Thursday,
but the Canadian/UKMET become less in line with upper ridge
amplification over the Bering Sea/Strait and downstream from
Northern Alaska to the Gulf of Alaska with systems digging into an
amplified/multi-center upper trough position Day 5/6 Friday into
Saturday. Embedded system differences in the models grow enough
into day 7/8 (next Sunday/Monday) to seem to justify a switch to
just an ensemble mean forecast approach. With the assumption the
aforementioned upper ridge builds near commonly advertised, the
ECMWF ensemble mean then seems more reasonable showing a less
progressive ridge/pattern by then than the GEFS mean. This
forecast plan seems to maintain reasonably good WPC Alaskan medium
range product suite continuity in a pattern with at least average
forecast predictability.
...Weather and Hazard Highlights...
Increased light to moderate precipitation chances are likely to
organize across portions of northern/Interior Alaska later this
week into next as upper disturbances and several surface fronts
work across the area. Meanwhile, a focus for moderate
precipitation should also linger over southern and southeastern
Alaska and the Panhandle into Thursday/Friday with slowly exiting
eastern Gulf of Alaska low proximity, but heavy totals are
generally not expected. Increased precipitation with moderate to
locally heavy totals are also possible next weekend into early
next week as a less certain deepened low and frontal system seems
set to works into the central to eastern Gulf of Alaska. River
flooding, significant in some places across the state, is expected
to be ongoing even with generally below to seasonal seasonal
Spring temperatures, ice jams, and snow melt.
Schichtel
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html